Stabilization of tetrahydrofuran



Patented Nov. 29, 1949 STABILIZATION F TETRAHYDROFURAN Charles A; Bordner, Niagara Falls, N. Y., assignor to E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application April 20, 1946, Serial No. 663,751

2 Claims. 1 This invention relates to the stabilization of heterocyclic organic compounds and in particular it relates to the stabilization of tetrahydrofuran.

Example A glass-stoppered clear glass bottle was half filled with freshly distilled anhydrous tetrahy- Tetrahydrofuran is a colorless liquid which is 5 of n n ining 0.1% pr s l- Th bo le potentially important and valuame compound containing the tetrahydrofuran and p-cresol was for the preparation of a wide variety of organic Stored in d f d light and an a y Of the compounds. An obstacle to its extensive use is peroxide content was made from time to time. the fact that it forms peroxides during storage. The nalysi fo p r xi nt n w s m d y Although freshly distilled tetrahydrofuran somepipetting a 10 0 mp f e y rof ran in o times contains small concentrations of peroxide, an excess f potassium iodide in dilute sulfuric in the order of a few hundredths of one per cent, acid Solution and al O the p e to stand which are relatively harmless, upon standing for in the da k dur 10 minutes. The liberated a comparatively short, period the peroxide corp iodine was then determined by titration With a tr ti rapidly increases t t point where standard sodium thiosulfate solution. The rethe material becomes unsafe to handle. Peroxide Suits are shown in tabular form below: formation in tetrahydrofuran not only introduces an undesirable impurity but also results in a 0 DOWN hazardous condition since the peroxide formed TimeinDays Thio s ulf atello 00. may decompose with explosive violence when Sample relatively high concentrations are present particularly when the material is distilled or heated. No method has heretofore been available for stabilizing tetrahydrofuran.

It is an object of this invention to provide a novel method for the stabilization of tetrahydrofuran. Another object is toinhibit peroxide formation in tetrahydrofuran. A further object is to provide a new stabilizer for tetrahydrofuran. An additional object is to provide a relatively stable tetrahydrofuran composition. These PE N??? mourners w-msnooozo A sample of tetrahydrofuran containing no p-cresol was tested as a control with the following results:

and other objects will be apparent from the fol- 0 3 5 N lowing description of my invention. TimeinDayS Thioslllfetelle The above objects are attained in accordance sample with my invention by incorporating into tetrastart 0 63 hydrofuran p-cresol. 3 IIIIIIII" III: 4140 I have discovered that when small amounts of '1'; p-cresol are incorporated into tetrahydrofuran peroxide formation is substantially inhibited and 1 a relatively stable composition results. Tetra- 40 furagl i s titt fifi hi afie iy tft tf, g rg i iii e i e ii hydrofuran stabilized in accordance with my invention may be stored over relatively long periods without the development of hazardous concentrations of peroxide.

Various concentrations of p-cresol may be utilized in the practice of my invention although I prefer to utilize concentrations within the range 0.05 to 1.0% by weight. Concentrations above 1.0% may be used successfully but in general amounts greater than 1.0% are unnecessary for satisfactory results. Less than 0.05% of p-cresol may be utilized but for consistently satisfactory results concentrations of more than 0.05% are desirable.

The following example illustrates my invention.

it is assumed that the peroxide contains one mole of tetrahydrofuran.

The foregoing data conclusively demonstrate the inhibiting effect of p-cresol on peroxide formation in tetrahydrofuran. Within 14 days, the unstabilized sample contained a higher concentration of peroxide than the stabilized sample developed in 122 days.

My invention provides a simple and economical means for stabilizing tetrahydrofuran. Not only may the stabilized material be stored over relatively long periods or shipped long distances without appreciable deterioration but also the hazard inherent in the presence of peroxides in the tetrahydrofuran is held to a minimum.

It claim: UNITED STATES PATENTS 1. The method for stabilizing tetrahydrofuran which comprises incorporating therein 0.05 to gigg g 1.0% of p-cresol.

2. A new stable tetrahydrofuran composition 5 2255483 DAleno Sept 1941 comprising tetrahydrofuran having incorporated FOREIGN PATENTS therein 0.05to-1'.0% ofp-cresol. Number, country Date CHARLES A BORDNER 181,365 Great Britain of 1923 10 OTHER REFERENCES FERENCES CITED Chem. Ab., v0l. 2a, 1934, page 5076 The following references are" of record in the Gilmans Organic Chemistry, vol. 1, 2nd ed.,

file of this patent: 1943, pp. 656, 657. 

